Contact-less tags, such as radio frequency identification (RFID) tags, are becoming increasingly commonplace in various commercial applications, two non-limiting examples of which include access control and inventory management.
An RFID tag affixed to an item stores a code (e.g., a bit pattern) that is output in contact-less fashion to a reader, either in response to a request from the reader or autonomously by the tag. The reader captures the bit pattern and then an action may be taken, depending on the commercial application at hand. For example, in an access control scenario, the captured bit pattern may reveal that the person presumed to be carrying the tag (by virtue of an association with the bit pattern) is—or is not—authorized to enter a building or operate a vehicle. In an inventory management scenario, the bit pattern may give an indication of items contained on a pallet, for example, which may result in certain decisions being taken regarding shipping or storage of these items.
In both cases, the ease with which an RFID tag may be read by a reader enables rapid processing but also may lead to problems. In the access control scenario, for example, an RFID tag of an individual authorized to access certain property may be interrogated and then the bit pattern cloned for use by an impostor to gain what is in fact unauthorized access to such property. Similarly, in the inventory management scenario, an acquired knowledge of the bit pattern associated with a certain item may allow a malicious party to gain intelligence about inventory locations that the item's rightful owner (which may include the manufacturer all the way down to the retail customer) may wish to keep secret.
In both of the above scenarios, it is apparent that what is relevant to a malicious party is the knowledge that a certain bit pattern output by a certain RFID tag will either give access to property or indicate the presence of a specific inventory item. Whether the bit pattern is itself an encrypted version of some original data is actually of no relevance to the malicious party. Thus, schemes based on straightforward encryption of the bit pattern do not mitigate the problems mentioned above.
Against this background, there is clearly a need in the industry for a contact-less tag having improved properties.